Hikvision "error message"

Dears,

good day to all.

can you please assist me as i am trying to connect the camera using P2P cloud via HIKVISION. however, when searching the serial number it give me error message " device is using by other user".

HIKVSION model DS-7200 Series

i am using iVMS-4500

i have already configure the port forwarding,

Hoping for your quick response and understanding.

Regards